Very neat!

One could also do it with a random image:

  wget http://quickimage.heroku.com/image/joker/80/60 -O- 2>/dev/null | icat -

(Assuming a high-speed low-latency connection otherwise terminal start-ups are slow.)

Or you could fork a process that downloads the image you are showing on the next time and show the last downloaded one directly to the console. That way the terminal start up will stay fast and you will get a new image on each new terminal :)